Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Single Molecules

BP 15.11: Vortrag

Mittwoch, 27. Februar 2008, 16:45–17:00, C 243

C-Ring conformational rotation of a single F0F1- ATP synthase motor using alternating laser excitation — •Stefan Ernst¹, Monika Düser¹, Nawid Zarrabi¹, Rolf Reuter¹, Stanley D. Dunn², Gary D. Glick³, and Michael Börsch¹ — ¹3rd Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany — ²Department of Biochemistry, University of Western Ontario, London, Ontario, Canada N6A 5C1 — ³Department of Chemistry, University of Michigan, Ann Arbor, MI, USA 48109- 1001

Formation of ATP from ADP and Phosphate (ATP synthese) is of great importance for any living cell. This chemical reaction is catalyzed by the enzyme F0F1- ATP synthase. By hydrolyzing ATP the enzyme can also work as an proton pump. Catalysis driven by a stepwise internal rotation of subunits of the lipid membrane embedded enzyme. To detect these substeps the single molecule fluorescence resonance energy trasfer (FRET) approach was used. We labeled one rotary c subunit with the FRET acceptor dye and the static a subunit with the FRET donor.

It was possible to determine the stepsize of rotation and dwell times. It was also possible to study the influence of different bacterial drugs, i.e. inhibitors of F0F1- ATP synthase like AMP-PNP and Aurovertin.

The different substep movements were identified with Hidden Markov Models (HMM). Duty cycle optimized alternating laser excitation provides an acceptor test to improve the accurancy of the single molecile FRET analysis.